hwrng: add per-device entropy derating
This patch introduces a derating factor to struct hwrng for
the random bits going into the kernel input pool, and a common
default derating for drivers which do not specify one.
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
index 3f075ff..914bb08 100644
--- a/include/linux/hw_random.h
+++ b/include/linux/hw_random.h
@@ -29,6 +29,8 @@
* @read: New API. drivers can fill up to max bytes of data
* into the buffer. The buffer is aligned for any type.
* @priv: Private data, for use by the RNG driver.
+ * @quality: Estimation of true entropy in RNG's bitstream
+ * (per mill).
*/
struct hwrng {
const char *name;
@@ -38,6 +40,7 @@
int (*data_read)(struct hwrng *rng, u32 *data);
int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
unsigned long priv;
+ unsigned short quality;
/* internal. */
struct list_head list;